Releasable connections, which still today are mostly common in tube-line systems of motor vehicles, are screw-type connections with screw caps. Relatively large torques must be applied during tightening of such connections. Such torques can result in damage, for example tearing loose of a welded-on connection onto which the screw cap is to be screwed. Connections, which are only rarely released, also can freeze up, particularly due to corrosion. The torques then needed for the release are greater yet so that the risk of damage also increases. It is also possible for screw caps to loosen due to vibrations, thereby resulting in leakage. In order to be able to apply tools to the screw cap, sufficient space must exist. The coupling and uncoupling of the screw connections is time-consuming. Incorrect coupling due to a skewed attaching of the screw cap often results in the destruction of the threads.
Plug-in connections, which are also used during the building of motor vehicles, do principally not have the mentioned disadvantages of screw connections. Also known (brochure sheet No. 1002/81 of Johannes Schaefer) is a plug-in connection of the abovementioned type for testing connections. The locking clip is in the known plug-in connection introduced with its legs into crossbores of the female part. This introduction is only possible after the plug-in connection has been created, thus requires a separate operation. In order to hold the clip so that it cannot be lost, same is tied to the female part by means of a plastic thread. Such a plug-in connection cannot be used everywhere, since the transverse movement of the locking clip can often not be carried out or can be carried out only with difficulties.
The basic purpose of the invention is to provide a plug-in connection of the abovementioned type such that the plug-in connection has a long lifetime, the locking clip can remain on the female part even after the connection has been released, and the plug-in connection is inexpensive to manufacture. A further purpose includes a securing of the plug-in connection in a simple manner against rotation and in making possible a pressure reduction through the plug-in connection prior to the release.
Through the possibility of movement of the legs of the locking clip, it is possible to move same into a release position without having to be pulled off from the female part. A difficult aligning of the locking clip with the crossbores on the female part is therefore not necessary. After creating the plug-in connection, a light pressure onto the already so to speak premounted locking clip is sufficient to move same into its locking position. It is also possible for the locking clip to assume its locking position already prior to the insertion of the male part. The legs are then spread apart during the insertion of the male part, which is particularly easy if a conical surface is provided for this purposes. The last-mentioned type of mounting is usually used.
The cavities in the female part can be constructed as two or four lateral slots. Such slots can easily be created through milling.
The legs can be spread apart preferably by pulling on the bar of the locking clip. This facilitates a particularly easy operation, since it is sufficient to grip, for example, with a screwdriver under the bar and to pull the bar slightly to the rear, the screwdriver functioning as a lever. The legs can, however, also be pressed together in the spread-apart position, so that they will then lie completely in the female part. The locking clip has then the shape of a Seeger ring.
The legs cooperating with the female part can be constructed particularly easily as bent end sections. The locking clip is preferably a one-piece structural part of wire, for example a wire with a circular cross section (other cross sections are also possible), whereby the wire ends can easily be flexed.
According to the further development of the invention, stops are provided for limiting the retracting movement of the locking clip. These can for example be constructed as milled recesses. This further simplifies the handling of the plug-in connection, since it is not possible, that the locking clip is, for example by mistake, pulled out too far and then becomes removed from the female part.
The construction of the legs of the locking clip with circular sections has the advantage that a large engaging length with the male-part locking groove exists, so that the specific pressure on the abutment points is maintained low.
The seal ring used for sealing has the advantage that the peripheral groove, when a rigid tube is to be connected, can be formed by the material of the tube. Only a small diameter is needed due to this construction. However, the peripheral groove for the seal can also be formed by tapping, for example in a male part, which is to be connected to a hose.
The spring arranged between the female part and the male part preferably presses both apart in axial direction, so that the plug-in connection is axially guyed. An axial guying of plug-in connections is actually known and has, however, in connection with the present invention the important advantage that the male part sits wobble-free in the female part and thus vibrations and more significant breakdowns are avoided. The spring is preferably constructed at the same time as a seal. The deformation of the seal can occur with the same conical surface, which is also used for spreading apart of the locking clip.
A guiding enlargement is preferably provided, which substantially simplifies the coupling, since a rough aligning of the male part on the female part is sufficient in order to start the plug-in process. The locking clip can particularly easily be pulled back, if a space for the engagement of a tool is provided. To protect against rotation of the male part and the female part, a cap is moved over both, which engages, for example, with a nose, both parts. The female part is constructed in two parts for facilitating a pressure reduction in the lines, whereby both parts are provided with a screw thread, through the threads of which, during a rotation out of the closed position, the pressure reduction occurs.